diff --git a/.github/workflows/os_comp.yml b/.github/workflows/os_comp.yml
index ce89573cf..b5aafa02d 100644
--- a/.github/workflows/os_comp.yml
+++ b/.github/workflows/os_comp.yml
@@ -11,7 +11,7 @@ jobs:
     - name: Install Dependencies
       run: |
         sudo apt update -yq
-        sudo apt install -yq --no-install-recommends g++ gfortran ninja-build gobjc gobjc++ zlib1g-dev
+        sudo apt install -yq --no-install-recommends python3-setuptools python3-pip g++ gfortran gobjc gobjc++ zlib1g-dev
     - name: Install ninja-build tool
       uses: seanmiddleditch/gha-setup-ninja@v1
     - name: Python version
@@ -22,3 +22,4 @@ jobs:
       run: python3 run_tests.py
       env:
         CI: '1'
+        XENIAL: '1'
diff --git a/run_project_tests.py b/run_project_tests.py
index c0adb8edc..e480160b1 100755
--- a/run_project_tests.py
+++ b/run_project_tests.py
@@ -94,6 +94,7 @@ class AutoDeletedDir:
 failing_logs = []
 print_debug = 'MESON_PRINT_TEST_OUTPUT' in os.environ
 under_ci = 'CI' in os.environ
+under_xenial_ci = under_ci and ('XENIAL' in os.environ)
 do_debug = under_ci or print_debug
 no_meson_log_msg = 'No meson-log.txt found.'
 
@@ -539,7 +540,8 @@ def have_java():
     return False
 
 def skippable(suite, test):
-    if not under_ci:
+    # Everything is optional when not running on CI, or on Ubuntu 16.04 CI
+    if not under_ci or under_xenial_ci:
         return True
 
     if not suite.endswith('frameworks'):
diff --git a/test cases/cmake/5 object library/main.cpp b/test cases/cmake/5 object library/main.cpp
index cdf54f1c3..9933ab457 100644
--- a/test cases/cmake/5 object library/main.cpp	
+++ b/test cases/cmake/5 object library/main.cpp	
@@ -1,3 +1,4 @@
+#include <stdlib.h>
 #include <iostream>
 #include "libA.hpp"
 #include "libB.hpp"
diff --git a/test cases/cmake/6 object library no dep/main.cpp b/test cases/cmake/6 object library no dep/main.cpp
index cdf54f1c3..9933ab457 100644
--- a/test cases/cmake/6 object library no dep/main.cpp	
+++ b/test cases/cmake/6 object library no dep/main.cpp	
@@ -1,3 +1,4 @@
+#include <stdlib.h>
 #include <iostream>
 #include "libA.hpp"
 #include "libB.hpp"
diff --git a/test cases/common/222 source set realistic example/meson.build b/test cases/common/222 source set realistic example/meson.build
index ea91e2991..5b0e4955a 100644
--- a/test cases/common/222 source set realistic example/meson.build	
+++ b/test cases/common/222 source set realistic example/meson.build	
@@ -1,7 +1,7 @@
 # a sort-of realistic example that combines the sourceset and kconfig
 # modules, inspired by QEMU's build system
 
-project('sourceset-example', 'cpp')
+project('sourceset-example', 'cpp', default_options: ['cpp_std=c++11'])
 
 cppid = meson.get_compiler('cpp').get_id()
 if cppid == 'pgi'
diff --git a/test cases/frameworks/1 boost/meson.build b/test cases/frameworks/1 boost/meson.build
index b528dca7c..2dce40d29 100644
--- a/test cases/frameworks/1 boost/meson.build	
+++ b/test cases/frameworks/1 boost/meson.build	
@@ -40,14 +40,10 @@ if(python2dep.found() and host_machine.system() == 'linux')
     # on the installed version of python (and hope that they match the version boost
     # was compiled against)
     py2version_string = ''.join(python2dep.version().split('.'))
-    bpython2dep = dependency('boost', modules : ['python' + py2version_string])
+    bpython2dep = dependency('boost', modules : ['python' + py2version_string], required: false, disabler: true)
   else
     # if we have an older version of boost, we need to use the old module names
-    bpython2dep = dependency('boost', modules : ['python'])
-  endif
-
-  if not (bpython2dep.found())
-    bpython2dep = disabler()
+    bpython2dep = dependency('boost', modules : ['python'], required: false, disabler: true)
   endif
 else
   python2dep = disabler()
@@ -57,13 +53,9 @@ endif
 if(python3dep.found() and host_machine.system() == 'linux')
   if(dep.version().version_compare('>=1.67'))
     py3version_string = ''.join(python3dep.version().split('.'))
-    bpython3dep = dependency('boost', modules : ['python' + py3version_string])
+    bpython3dep = dependency('boost', modules : ['python' + py3version_string], required: false, disabler: true)
   else
-    bpython3dep = dependency('boost', modules : ['python3'])
-  endif
-
-  if not (bpython3dep.found())
-    bpython3dep = disabler()
+    bpython3dep = dependency('boost', modules : ['python3'], required: false, disabler: true)
   endif
 else
   python3dep = disabler()
diff --git a/test cases/frameworks/6 gettext/meson.build b/test cases/frameworks/6 gettext/meson.build
index 09ef9829e..afa24b1d5 100644
--- a/test cases/frameworks/6 gettext/meson.build	
+++ b/test cases/frameworks/6 gettext/meson.build	
@@ -5,6 +5,11 @@ if not gettext.found()
   error('MESON_SKIP_TEST gettext not found.')
 endif
 
+xgettext = find_program('xgettext', required: false)
+if not xgettext.found()
+  error('MESON_SKIP_TEST xgettext not found.')
+endif
+
 if not meson.get_compiler('c').has_header('libintl.h')
   error('MESON_SKIP_TEST libintl.h not found.')
 endif
diff --git a/test cases/frameworks/7 gnome/meson.build b/test cases/frameworks/7 gnome/meson.build
index 03335b885..e7ba56578 100644
--- a/test cases/frameworks/7 gnome/meson.build	
+++ b/test cases/frameworks/7 gnome/meson.build	
@@ -5,6 +5,11 @@ if not glib.found()
   error('MESON_SKIP_TEST glib not found.')
 endif
 
+gir = dependency('gobject-introspection-1.0', required: false)
+if not gir.found()
+  error('MESON_SKIP_TEST gobject-introspection not found.')
+endif
+
 python3 = import('python3')
 py3 = python3.find_python()
 if run_command(py3, '-c', 'import gi;').returncode() != 0